* [PATCH v2] block: Use LVM tools for LV block device truncation
@ 2024-03-13 10:43 Alexander Ivanov
2024-03-14 12:44 ` Daniel P. Berrangé
0 siblings, 1 reply; 4+ messages in thread
From: Alexander Ivanov @ 2024-03-13 10:43 UTC (permalink / raw)
To: qemu-devel
Cc: qemu-block, den, andrey.drobyshev, jsnow, vsementsov, kwolf,
hreitz
If a block device is an LVM logical volume we can resize it using
standard LVM tools.
Add a helper to detect if a device is a DM device. In raw_co_truncate()
check if the block device is DM and resize it executing lvresize.
Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
block/file-posix.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/block/file-posix.c b/block/file-posix.c
index 35684f7e21..5f07d98aa5 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd, int64_t offset,
return raw_thread_pool_submit(handle_aiocb_truncate, &acb);
}
+static bool device_is_dm(struct stat *st)
+{
+ unsigned int maj, maj2;
+ char line[32], devname[16];
+ bool ret = false;
+ FILE *f;
+
+ if (!S_ISBLK(st->st_mode)) {
+ return false;
+ }
+
+ f = fopen("/proc/devices", "r");
+ if (!f) {
+ return false;
+ }
+
+ maj = major(st->st_rdev);
+
+ while (fgets(line, sizeof(line), f)) {
+ if (sscanf(line, "%u %15s", &maj2, devname) != 2) {
+ continue;
+ }
+ if (strcmp(devname, "device-mapper") == 0) {
+ ret = (maj == maj2);
+ break;
+ }
+ }
+
+ fclose(f);
+ return ret;
+}
+
static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
BdrvRequestFlags flags, Error **errp)
@@ -2670,6 +2702,35 @@ static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
int64_t cur_length = raw_getlength(bs);
+ /*
+ * Try to resize an LVM device using LVM tools.
+ */
+ if (device_is_dm(&st) && offset > 0) {
+ int spawn_flags = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL;
+ int status;
+ bool success;
+ char *err;
+ GError *gerr = NULL;
+ g_autofree char *size_str = g_strdup_printf("%ldB", offset);
+ const char *cmd[] = {"lvresize", "-f", "-L",
+ size_str, bs->filename, NULL};
+
+ success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
+ NULL, NULL, NULL, &err, &status, &gerr);
+
+ if (success && WEXITSTATUS(status) == 0) {
+ return 0;
+ }
+
+ if (!success) {
+ error_setg(errp, "lvresize execution error: %s", gerr->message);
+ } else {
+ error_setg(errp, "%s", err);
+ }
+
+ return -EINVAL;
+ }
+
if (offset != cur_length && exact) {
error_setg(errp, "Cannot resize device files");
return -ENOTSUP;
--
2.40.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] block: Use LVM tools for LV block device truncation
2024-03-13 10:43 [PATCH v2] block: Use LVM tools for LV block device truncation Alexander Ivanov
@ 2024-03-14 12:44 ` Daniel P. Berrangé
2024-03-14 17:25 ` Alexander Ivanov
0 siblings, 1 reply; 4+ messages in thread
From: Daniel P. Berrangé @ 2024-03-14 12:44 UTC (permalink / raw)
To: Alexander Ivanov
Cc: qemu-devel, qemu-block, den, andrey.drobyshev, jsnow, vsementsov,
kwolf, hreitz
On Wed, Mar 13, 2024 at 11:43:27AM +0100, Alexander Ivanov wrote:
> If a block device is an LVM logical volume we can resize it using
> standard LVM tools.
>
> Add a helper to detect if a device is a DM device. In raw_co_truncate()
> check if the block device is DM and resize it executing lvresize.
>
> Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
> ---
> block/file-posix.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 35684f7e21..5f07d98aa5 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd, int64_t offset,
> return raw_thread_pool_submit(handle_aiocb_truncate, &acb);
> }
> static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
> bool exact, PreallocMode prealloc,
> BdrvRequestFlags flags, Error **errp)
> @@ -2670,6 +2702,35 @@ static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
> if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
> int64_t cur_length = raw_getlength(bs);
>
> + /*
> + * Try to resize an LVM device using LVM tools.
> + */
> + if (device_is_dm(&st) && offset > 0) {
> + int spawn_flags = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL;
> + int status;
> + bool success;
> + char *err;
> + GError *gerr = NULL;
> + g_autofree char *size_str = g_strdup_printf("%ldB", offset);
offset is 64-bit, but '%ld' is not guaranteed to be 64-bit. I expect
this will break on 32-bit platforms. Try PRId64 instead.
> + const char *cmd[] = {"lvresize", "-f", "-L",
> + size_str, bs->filename, NULL};
> +
> + success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
> + NULL, NULL, NULL, &err, &status, &gerr);
> +
> + if (success && WEXITSTATUS(status) == 0) {
> + return 0;
> + }
We should probably check 'g_spawn_check_wait_status' rather than
WEXITSTATUS, as this then gives us further eror message details
that....
> +
> + if (!success) {
> + error_setg(errp, "lvresize execution error: %s", gerr->message);
> + } else {
> + error_setg(errp, "%s", err);
...we would also include here, such as the exit code or terminal
signal.
> + }
> +
> + return -EINVAL;
> + }
> +
> if (offset != cur_length && exact) {
> error_setg(errp, "Cannot resize device files");
> return -ENOTSUP;
> --
> 2.40.1
>
>
With regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] block: Use LVM tools for LV block device truncation
2024-03-14 12:44 ` Daniel P. Berrangé
@ 2024-03-14 17:25 ` Alexander Ivanov
2024-03-14 17:28 ` Daniel P. Berrangé
0 siblings, 1 reply; 4+ messages in thread
From: Alexander Ivanov @ 2024-03-14 17:25 UTC (permalink / raw)
To: Daniel P. Berrangé
Cc: qemu-devel, qemu-block, den, andrey.drobyshev, jsnow, vsementsov,
kwolf, hreitz
On 3/14/24 13:44, Daniel P. Berrangé wrote:
> On Wed, Mar 13, 2024 at 11:43:27AM +0100, Alexander Ivanov wrote:
>> If a block device is an LVM logical volume we can resize it using
>> standard LVM tools.
>>
>> Add a helper to detect if a device is a DM device. In raw_co_truncate()
>> check if the block device is DM and resize it executing lvresize.
>>
>> Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
>> ---
>> block/file-posix.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 61 insertions(+)
>>
>> diff --git a/block/file-posix.c b/block/file-posix.c
>> index 35684f7e21..5f07d98aa5 100644
>> --- a/block/file-posix.c
>> +++ b/block/file-posix.c
>> @@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd, int64_t offset,
>> return raw_thread_pool_submit(handle_aiocb_truncate, &acb);
>> }
>> static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
>> bool exact, PreallocMode prealloc,
>> BdrvRequestFlags flags, Error **errp)
>> @@ -2670,6 +2702,35 @@ static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
>> if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
>> int64_t cur_length = raw_getlength(bs);
>>
>> + /*
>> + * Try to resize an LVM device using LVM tools.
>> + */
>> + if (device_is_dm(&st) && offset > 0) {
>> + int spawn_flags = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL;
>> + int status;
>> + bool success;
>> + char *err;
>> + GError *gerr = NULL;
>> + g_autofree char *size_str = g_strdup_printf("%ldB", offset);
> offset is 64-bit, but '%ld' is not guaranteed to be 64-bit. I expect
> this will break on 32-bit platforms. Try PRId64 instead.
>
>> + const char *cmd[] = {"lvresize", "-f", "-L",
>> + size_str, bs->filename, NULL};
>> +
>> + success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
>> + NULL, NULL, NULL, &err, &status, &gerr);
>> +
>> + if (success && WEXITSTATUS(status) == 0) {
>> + return 0;
>> + }
> We should probably check 'g_spawn_check_wait_status' rather than
> WEXITSTATUS, as this then gives us further eror message details
> that....
Thank you.
I think it would be better to use 'g_spawn_check_exit_status' because
there is no
'g_spawn_check_wait_status' in glib before 2.70 and even in 2.78 it
leads to
'g_spawn_check_wait_status is deprecated: Not available before 2.70' error.
>
>> +
>> + if (!success) {
>> + error_setg(errp, "lvresize execution error: %s", gerr->message);
>> + } else {
>> + error_setg(errp, "%s", err);
> ...we would also include here, such as the exit code or terminal
> signal.
>
>> + }
>> +
>> + return -EINVAL;
>> + }
>> +
>> if (offset != cur_length && exact) {
>> error_setg(errp, "Cannot resize device files");
>> return -ENOTSUP;
>> --
>> 2.40.1
>>
>>
> With regards,
> Daniel
--
Best regards,
Alexander Ivanov
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] block: Use LVM tools for LV block device truncation
2024-03-14 17:25 ` Alexander Ivanov
@ 2024-03-14 17:28 ` Daniel P. Berrangé
0 siblings, 0 replies; 4+ messages in thread
From: Daniel P. Berrangé @ 2024-03-14 17:28 UTC (permalink / raw)
To: Alexander Ivanov
Cc: qemu-devel, qemu-block, den, andrey.drobyshev, jsnow, vsementsov,
kwolf, hreitz
On Thu, Mar 14, 2024 at 06:25:00PM +0100, Alexander Ivanov wrote:
>
>
> On 3/14/24 13:44, Daniel P. Berrangé wrote:
> > On Wed, Mar 13, 2024 at 11:43:27AM +0100, Alexander Ivanov wrote:
> > > If a block device is an LVM logical volume we can resize it using
> > > standard LVM tools.
> > >
> > > Add a helper to detect if a device is a DM device. In raw_co_truncate()
> > > check if the block device is DM and resize it executing lvresize.
> > >
> > > Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
> > > ---
> > > block/file-posix.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++
> > > 1 file changed, 61 insertions(+)
> > >
> > > diff --git a/block/file-posix.c b/block/file-posix.c
> > > index 35684f7e21..5f07d98aa5 100644
> > > --- a/block/file-posix.c
> > > +++ b/block/file-posix.c
> > > @@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd, int64_t offset,
> > > return raw_thread_pool_submit(handle_aiocb_truncate, &acb);
> > > }
> > > static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
> > > bool exact, PreallocMode prealloc,
> > > BdrvRequestFlags flags, Error **errp)
> > > @@ -2670,6 +2702,35 @@ static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
> > > if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
> > > int64_t cur_length = raw_getlength(bs);
> > > + /*
> > > + * Try to resize an LVM device using LVM tools.
> > > + */
> > > + if (device_is_dm(&st) && offset > 0) {
> > > + int spawn_flags = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL;
> > > + int status;
> > > + bool success;
> > > + char *err;
> > > + GError *gerr = NULL;
> > > + g_autofree char *size_str = g_strdup_printf("%ldB", offset);
> > offset is 64-bit, but '%ld' is not guaranteed to be 64-bit. I expect
> > this will break on 32-bit platforms. Try PRId64 instead.
> >
> > > + const char *cmd[] = {"lvresize", "-f", "-L",
> > > + size_str, bs->filename, NULL};
> > > +
> > > + success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
> > > + NULL, NULL, NULL, &err, &status, &gerr);
> > > +
> > > + if (success && WEXITSTATUS(status) == 0) {
> > > + return 0;
> > > + }
> > We should probably check 'g_spawn_check_wait_status' rather than
> > WEXITSTATUS, as this then gives us further eror message details
> > that....
> Thank you.
> I think it would be better to use 'g_spawn_check_exit_status' because there
> is no
> 'g_spawn_check_wait_status' in glib before 2.70 and even in 2.78 it leads to
> 'g_spawn_check_wait_status is deprecated: Not available before 2.70' error.
Ah yes, well spotted.
With regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
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2024-03-13 10:43 [PATCH v2] block: Use LVM tools for LV block device truncation Alexander Ivanov
2024-03-14 12:44 ` Daniel P. Berrangé
2024-03-14 17:25 ` Alexander Ivanov
2024-03-14 17:28 ` Daniel P. Berrangé
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